The present invention is directed to a joystick having at least one degree of control in addition to the traditional X control and Y control. More particularly, the present invention is directed to a joystick having a shaft which can be manually moved in the X and Y directions to control X and Y potentiometers, and which can also be manually rotated and/or moved along its axis to actuate at least one further control element such as a potentiometer or switch.
A joystick is an electromechanical control device having a shaft which an operator can pivot in various directions. Perhaps the best-known application for joysticks is to control electronic games, but other uses such as cursor control on computer displays or steering control of vehicles are also known. In a typical conventional joystick two yoke elements are mounted at right angles to each other so that they are individually pivotable. Each yoke element is coupled to a respective potentiometer. Furthermore each yoke element has an elongated slot through which the shaft extends, so that manual movement of the shaft in any direction is coupled, depending upon the direction and magnitude of the shaft's movement, to the potentiometers by way of the yokes. A conventional joystick such as this provides X-Y control.
In view of the general usefulness of X-Y control as provided by the conventional joystick described above, it is not surprising that attempts have been made to design joysticks with one or more further degrees of control, such as Z-axis control or rotational control. For example, U.S. Pat. No. 4,156,130 discloses a joystick with a first potentiometer which is mounted on a chassis, a second potentiometer which is mounted on the shaft of the first potentiometer and which is disposed at right angles to the first potentiometer, a third potentiometer which is mounted on the shaft of the second potentiometer and which is disposed at right angles to both the first and second potentiometers, and a linear-motion-type potentiometer which connects the control lever of the joystick to the shaft of the third potentiometer. As a result of this construction the joystick of U.S. Pat. No. 4,156,130 permits both Z-axis control and rotational control, about the Z axis, in addition to the conventional X-Y control.
However joysticks with more than X-Y control tend to be either flimsy or mechanically complicated, which leads to increased expense. Accordingly, it would be desirable to provide an improved joystick which is both sufficiently rugged and sufficiently inexpensive to permit at least one additional degree of control in practical situations.